8, 175 is directly related to rollout in manual mode. You seem to confuse auto land with rollout. CAT III A requires autoland with an option of exceptionally completing the landing in manual mode only with DH 50ft and RVR 200 in EU OPS. No such option for FAA or ICAO as TDZ RVR 175 isn't sufficient to accomplish landing manually. However it doesn't preclude a manual rollout which in turn requires a min RVR. 175 is very conservative figure whereas EU OPS is happy with 125. On the other hand EU OPS asks for 75 M to be able to taxi and for emergency services whereas ICAO goes as low as 50m. It's directly related to fail operational concept for both autoland and optional manual rollout. As a consequence one ought to insert DH of 50 ft in case being fail passive on CAT III A resulting in a requirement for a visual segment at DH and NO visual cues requirements at AH in case of fail operational. Now auto land and rollout are cohesive, aren't they? You can't have fail passive autoland and fail operational rollout system at the same time, can you? Thus 175 M is for CAT III A with fail passive auto rollout system.
